Motor fuel compositions



Uni :5 States 3,047,374 MOTOR FUEL COMPOSITIONS Albert C. Condo, Jr., Newtown Square, Pa., assignor to The Atlantic Refining Company, Philadelphia, Pa., a corporation of Pennsylvania N Drawing. Filed Mar. 2, 1960, Ser. No. 12,264 4 Claims. (Cl. 44-69) This invention relates to improvements in motor fuels in the gasoline boiling range and in particular to such motor fuels, the effect of which will be to reduce the octane requirement increase and thus inhibit surface ignition in internal combustion engines. Specifically, this invention has to do with motor fuels to which has been added a fluorine-containing organic compound.

The recent trend in internal combustion engines has been toward higher compression ratios for which there is required a motor fuel having a compensating octane number. Moderately high octane number fuels have been found to satisfy the octane requirements of the engines while the engines are new but after only a few months of operation, i.e., two to six months, these same engines have been found to require increasingly higher octane number fuels.

This increase in octane requirement that an engine may experience following this relatively short period of use is termed octane number requirement increase and is usually abbreviated to ORI. ORI is the result of combustion chamber deposits. These deposits decrease the physical volume of the combustion chamber and thus in effect increase the compression ratio of the engine which in turn raises the octane number requirement of the engine. They also have a heat insulating effect which reduces the rate of heat transfer from the combustion chamber to the cooling system. This latter causes excessive heat to be transferred to the incoming air-fuel mixture which sensitizes the mixture and promotes autoignition. Thus as the engine is operated, the amount of deposits increases and the octane number requirement increases. Moreover, it has been suggested also that these deposits produce hot spots in the combustion chamber with resultant preignition; that is, the hot, incandescent spot in the combustion chamber will cause the explosion of the gasoline-air mixture instead of the explosion being caused by the firing of the spark plug. This ignition generally occurs prior to the firing of the spark plug and hence this phenomenon is often termed preignition or surface ignition. Preignition or surface ignition often produces an effect similar to that of the knocking of 10W octane number fuels in a high octane requirement situation.

Accordingly it is an object of this invention to provide a motor fuel composition comprising a major amount of hydrocarbons boiling in the gasoline range and a minor amount of an additive sufiicient to reduce the octane requirement increase of an internal combustion engine.

It is a further object of this invention to provide a motor fuel composition comprising a major amount of hydrocarbons boiling in the gasoline boiling range and a minor amount. of a fluorine-containing organic compound sufiicient to reduce the octane requirement increase of internal combustion engines.

Further objects of this invention will be apparent from the description and claims that follow.

In accordance with the instant invention a fluorinecontaining organic compound is added to gasoline in minor amounts. These compounds are added preferably to a gasoline containing tetraethyl lead since the bulk of the gasoline presently being produced is leaded and it is the improvement of such fuels that is the primary purpose of this invention. The tetraethyl lead anti-knock ice agent is employed in conventional amounts and contains the normal scavenging agents. may contain minor and conventional amounts of other additives such as solvent oils, gum inhibitors, dyes, lead 5 stabilizers, carburetor anti-icing agents, and similar additives.

The amount of fluorine-containing organic compound which is added to the gasoline is preferably measured in grams of compound per gallon of gasoline. It has been found that the octane requirement increase of an internal combustion engine may be substantially reduced by adding to the gasoline a fluorine-containing organic compound in an amount ranging between about 0.1 gram of compound per gallon of gasoline to about 3.5 grams of compound per gallon of gasoline. For best results, however, amounts ranging between about 0.17 gram of compound per gallon of gasoline to about 1.15 grams of compound per gallon of gasoline are preferred.

The fluorine-containing organic compounds suitable for use as gasoline additives in accordance with this invention have the general formula:

Rz-O wherein R and R are radicals selected from the group consisting of alkyl, aryl, alkaryl, aralkyl, fluoroalkyl, fluoro-alkaryl, and fluoro-aralkyl and wherein at least one of the radicals R and R is fluorine-substituted, the

total number of carbon atoms in the molecule ranges between 3 and 30 and the total number of fluorine atoms in the molecule ranges between 2 and 16. In addition, any carbon atom which is fluorine-substituted bears at least 2 fluorine atoms and, in the case of terminal carbon atoms, may bear 3 fluorine atoms. In general, these compounds are prepared by condensing a fluoro alcohol with a carbonyl chloride.

The preferred compound for use in conjunction with the gasoline component of this invention is bis(trifluoroethyl) carbonate and has the following structural formula:

CF -OHz-O CFa-CHPO Other typical compounds included within the scope of this invention have structural formulas as follows:

The following examples will serve to illustrate the preferred mode for carrying out the instant invention and to further define its scope and usefulness which examples are not to be construed as limitative.

Example I Various fuel compositions were tested in a Briggs and Stratton, Model S-S, single cylinder, air cooled, L-head Patented July 31, 1962- In addition, the gasoline spe'zgsve internal combustion engine. The base gasoline employed was a commercial premium gasoline containing a blend of C hydrocarbons, catalytically reformed naphtha and catalytically cracked naphtha together with isobutanebutylene alkylate. This gasoline had a boiling range of 90 F. to 420 F. and contained 3 cc. of conventional tetraethyl lead fluid per gallon. The lubricant employed was a conventional premium grade detergent-inhibitor additive lubricating oil of SAE 20 grade.

The engine was first run for 20 hours on the conventional gasoline fuel during which time the octane requirement of the engine increased from 62 to 71, i.e., an increase of 9 octane numbers. After the run the engine was dismantled and'the interior surfaces of the combustion chamber and exhaust valve were cleaned of deposits. A new spark plug was used for each run.

After reassembly the engine was operated for a period of 20 hours on the same gasoline, however, in this run the gasoline contained 0.68 gram of bis(trifluoroethyl) carbonate per gallon of the gasoline. During this run the octane requirement of the engine increased only 2 numbers, i.e., from 62 to 64.

After disassembly, cleaning, and reassembly the engine was operated for 20 hours on the same conventional gasoline which contained no additive specifically to reduce ORI. During this run the octane requirement of the engine increased'from 62 to 71, i.e., an increase of 9 octane numbers. After the run the engine was dismantled and the internal surfaces of the combustion chamber and exhaust valve were cleaned of deposits.

After reassembly the engine was operated for a period of 20 hours on the same conventional gasoline which contained 0.17 gram of bis(trifluoroethy1) carbonate per gallon of gasoline. During this run the octane require ment of the engine increased only 4 numbers, i.e., from 62 to 66. a

The engine was again disassembled, cleaned, reassembled and operated for a period of 20 hours on the same conventional gasoline containing no additive. During this run the octane requirement of the engine increased 9 octane numbers, i.e., from 62 to 71.

The engine was again disassembled, cleaned, reassembled and operated for a period of 20 hours on the same conventional gasoline which contained 0.68 gram of bis- (trifluoroethyl) carbonate per gallon of gasoline. During this run the octane requirement of the engine increased only 3 numbers i.e., from 62 to 65.

Each type of run described above was repeated a number of times in a randomized order with the ORI number determined each time, and with disassembly, cleaning, and reassembly of the engine between each run. The results of these runs are set forth in Table I below.

These data clearly show that when an engine is operated with a conventional gasoline containing no additive to reduce ORI the octane requirement increase of the engine is substantially higher than when the same engine is operated with a similar fuel containing the preferred amounts of fluorine-containing organic compounds according to this invention. In addition these data clearly show that a substantial reduction in URI is obtained with each run when using the preferred compounds of this invention, since it is shown above that a blank run was performed both before and after the actual testing of the preferred compounds according to this invention.

I claim:

1. A gasoline motor fuel comprising a major amount of hydrocarbons boiling in the gasoline boiling range and a minor amount of a fluorine-containing organic compound sufiicient to reduce octane requirement increase in an internal combustion engine, the fluorine-containing organic compound having the general formula:

wherein R and R are radicals selected from the group consisting of alkyl, alkaryl, and fluoro-alkyl and wherein at least one of the radicals R and R is fluorine'substituted, the total number of carbon atoms in the molecule ranges between 3 and 30, the total number of fluorine atoms in the molecule ranges between 2 and 16, and each fluorine substituted carbon atom has at least two fluorine atoms attached thereto.

2. A gasoline motor fuel comprising a major amount of hydrocarbons boiling in the gasoline range and con taining tetraethyllead anti-k-nock agent together with a minor amount of a fluorine-containing organic compound in an amount ranging between about 0.10 to about 3.50 grams of fluorine-containing compound per gallon of gasoline, the fluorine-containing organic compound having the general formula:

RIF-O Rr-O wherein R and R are radicals selected from the group consisting of alkyl, 'alkaryl, and fluoro-a'lkyl and wherein at least one of the radicals R and R is fluorine-substituted, the total number of carbon atoms in the moleculeranges between 3 and 30, the total number of fluorine atoms in the molecule ranges between 2 and 16, and each fluorine substituted carbon atom has at least two fluorine atoms attached thereto.

3. A gasoline motor fuel comprising a major amount of hydrocarbons boiling in the gasoline range and containing tetraethyllead anti-knock agent together with bis- (trifluoroethyl) carbonate in an amount ranging between about 0.10 to about 3.50 grams of bis(trifluoroethyl) carbonate per gallon of gasoline.

4. A gasoline motor fuel comprising a major amount of hydrocarbons boiling in the gasoline range and containing tetraethyllead anti-knock agent together with bis- (trifluoroethyl) carbonate in an amount ranging between about 0.17 to about 1.14 grams of bis(trifluoroethyl) car bonate per gallon of gasoline.

References Cited in the file of this patent UNITED STATES PATENTS 2,214,768 Lincoln Sept. 17, 1940 2,281,598 Pnl-tton May 5, 1942 2,331,386 Gaylor Oct. 12, 1943 2,789,891 Brandes et a1 Apr. 23, 1957 2,844,448 Heisler et a1. July 22, 1958 2,844,450 Heisler et al. July 22, 1958 2,935,479 Oberdorfer May 3, 1960 

1. A GASOLINE MOTOR FUEL COMPRISING A MAJOR AMOUNT OF HYDROCARBONS BOILING IN THE GASOLINE BOILING RANGE AND A MINOR AMOUNT OF A FLUORINE-CONTAINING ORGANIC COMPOUND SUFFICIENT TO REDUC OCTANE REQUIREMENT INCREASE IN AN INTERNAL COMBUSTION ENGINE, THE FLUORINE-CONTAINING ORGANIC COMPOUND HAVING THE GENERAL FORMULA: 